WO2024001505A1

WO2024001505A1 - Display system and display apparatus

Info

Publication number: WO2024001505A1
Application number: PCT/CN2023/091888
Authority: WO
Inventors: 赵伟利
Original assignee: 京东方科技集团股份有限公司; 北京京东方显示技术有限公司
Priority date: 2022-06-29
Filing date: 2023-04-28
Publication date: 2024-01-04
Also published as: CN115047628A

Abstract

The present application relates to a display system and a display apparatus. The display system comprises a display module, which is used for emitting light, wherein a linear polarizer is attached to the display module and is used for generating linearly polarized light. In an optical path from the display module to an eye side, the display system further comprises a switchable first quarter-wave plate, a first lens, a semi-reflective and semi-transparent lens, a switchable second quarter-wave plate and a reflective polarizer, wherein the first quarter-wave plate and the second quarter-wave plate are both have electrodes, the first quarter-wave plate is driven under a first voltage, and the second quarter-wave plate is driven under a second voltage, such that the display system generates an image of a first depth of field; and the first quarter-wave plate is driven under the first voltage, and the second quarter-wave plate is driven under a third voltage, such that the display system generates an image of a second depth of field, the first depth of field being different from the second depth of field. The display system and display apparatus in the present application can realize the monocular multi-depth-of-field VR display.

Description

Display system and display device

Technical field

The present application relates to the field of optical imaging technology, and in particular, to a display system and a display device.

Background technique

Currently, VR (Virtual Reality) devices on the market usually use conventional binocular parallax 3D displays. The left and right eyes respectively see the left and right eye images at a certain depth of field, thereby producing a three-dimensional picture in the brain.

Contents of the invention

The purpose of the embodiments of the present application is to provide a display system and a display device that can realize single-eye multi-depth VR display.

One aspect of embodiments of the present application provides a display system. The display system includes a display module for emitting light. A linear polarizer is attached to the display module for generating linearly polarized light. The display system also has a light path from the display module to the eye side. It includes a switchable first quarter-wave plate, a first lens, a half-reflective half-mirror, a switchable second quarter-wave plate and a reflective polarizer, the first quarter-wave plate and the Each of the second quarter-wave plates has an electrode, the first quarter-wave plate is driven at a first voltage and the second quarter-wave plate is driven at a second voltage so that the A display system produces an image with a first depth of field, the first quarter wave plate is driven at the first voltage and the second quarter wave plate is driven at a third voltage such that the display system An image with a second depth of field is produced, wherein the first depth of field is different from the second depth of field.

Another aspect of embodiments of the present application provides a display device. The display device includes a display system as described above.

The display system and display device of one or more embodiments of the present application use a shearable wave plate, and the voltage applied to the wave plate can make the wave plate operate in several optical states at a higher frequency. Switch between and match with other optical devices, so that multiple different focal lengths and virtual image distances can be generated, and the 2D source of the display module can be used to display different information at multiple times. Through time division multiplexing, the People see multiple images with different virtual image distances, realizing VR display with multiple depths of field per eye.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.

Figure 1 is a schematic diagram of an optical path when the display system according to the first embodiment of the present application has a first optical path;

Figure 2 is a schematic diagram of the optical path of the display system according to the first embodiment of the present application when it has a second optical path;

Figure 3 is a schematic diagram of the optical path of the display system according to the second embodiment of the present application when it has a first optical path;

Figure 4 is a schematic diagram of the optical path of the display system according to the second embodiment of the present application when it has a second optical path;

Figure 5 is a schematic diagram of the optical path of the display system according to the second embodiment of the present application when it has a third optical path;

Figure 6 is a schematic diagram of the optical path of the display system according to the second embodiment of the present application when it has a fourth optical path;

Figure 7 is a schematic diagram of the optical path of the liquid crystal half-wave plate before and after power-on according to an embodiment of the present application;

Figure 8 is a schematic cross-sectional view of the annular electrode of the second liquid crystal quarter-wave plate according to an embodiment of the present application;

FIG. 9 is a schematic diagram of the optical path of the second liquid crystal quarter-wave plate under application of different voltages according to an embodiment of the present application.

Detailed ways

Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings refer to the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely related to some aspects of the present application as detailed in the appended claims. Examples of devices that are consistent in aspects.

The terminology used in the embodiments of the present application is only for the purpose of describing specific embodiments and is not intended to limit the present application. Unless otherwise defined, the technical terms or scientific terms used in the embodiments of this application should have the usual meanings understood by those with ordinary skills in the field to which this application belongs. "First", "second" and similar words used in the description and claims of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Likewise, "a" or "one" and similar words do not indicate a quantitative limit, but rather indicate the presence of at least one. "Multiple" or "several" means two or more than two. Unless otherwise indicated, similar terms such as "front", "rear", "lower" and/or "upper" are for convenience of description only and are not intended to limit one position or one spatial orientation. "Including" or "including" and other similar words mean that the elements or objects appearing before "includes" or "includes" cover the elements or objects listed after "includes" or "includes" and their equivalents, and do not exclude other elements. or objects. Words such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. As used in this specification and the appended claims, the singular forms "a," "the" and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It will also be understood that the term "and/or" as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

First embodiment

FIG. 1 shows a schematic diagram of the optical path of the display system 20 according to the first embodiment of the present application when it has a first optical path. FIG. 2 shows a schematic diagram of the optical path of the display system 20 according to the first embodiment of the present application when it has a second optical path. As shown in Figures 1 and 2, the display system 20 of the first embodiment of the present application includes a display module 21 for emitting light. A linear polarizer (L-pol) 23 is attached to the display module 21 and can be used to Produces linearly polarized light. The optical path from the display module 21 to the eye side of the display system 20 also includes a switchable first quarter wave plate (QWP, Quarter Wave Plate) (referred to as QWP1), a first lens 25, a half-reflective half-lens ( Half mirror) 26, a switchable second quarter wave plate (QWP2) 27 and a reflective polarizer (ReP, Reflective Polarizer) 28.

In some embodiments, the switchable first quarter-wave plate includes a first liquid crystal (LC, Liquid Crystal) quarter-wave plate 24; and/or a switchable second quarter-wave plate A second liquid crystal quarter wave plate 27 is included. Of course, the first quarter-wave plate and the second quarter-wave plate in the embodiment of the present application are not limited to the form of liquid crystal wave plates. In other embodiments, the switchable third quarter-wave plate in the embodiment of the present application is A quarter-wave plate and a switchable second quarter-wave plate can also be implemented in other forms capable of changing the optical state of the wave plate. In the following, the switchable first quarter-wave plate is used as the first liquid crystal quarter-wave plate 24 and the switchable second quarter-wave plate is used as the second liquid crystal quarter-wave plate 27 as an example. for a schematic explanation.

The display system 20 of the embodiment of the present application combines the first liquid crystal quarter-wave plate 24, the first liquid crystal quarter-wave plate 24 and the second liquid crystal four-wave plate on the basis of attaching the linear polarizer 23 to the display module 21. The half-wave plate 27 is a liquid crystal wave plate of the same design. Therefore, there is no problem of wavelength dispersion matching, which greatly improves the initiative of the design.

The first liquid crystal quarter-wave plate 24 and the second liquid crystal quarter-wave plate 27 in the embodiment of the present application both have electrodes and a liquid crystal layer located between the electrodes. The first liquid crystal quarter-wave plate 24 can have different optical states when driven by different voltages, and the second liquid crystal quarter-wave plate 27 can also have different optical states when driven by different voltages.

In some embodiments, the first liquid crystal quarter-wave plate 24 is driven at a first voltage and the second liquid crystal quarter-wave plate 27 is driven at a second voltage to cause the display system to produce an image with a first depth of field, The first liquid crystal quarter-wave plate 24 is driven at the first voltage and the second liquid crystal quarter-wave plate 27 is driven at a third voltage to cause the display system 20 to produce an image with a second depth of field, wherein the first Depth of field is different from second depth of field. Therefore, by applying the voltage on the electrodes of the first liquid crystal quarter-wave plate 24 and the voltage on the electrodes of the second liquid crystal quarter-wave plate 27, the display system 20 of the embodiment of the present application can generate the first The image of the depth of field and the image of the second depth of field. For example, the first voltage and the third voltage may be low voltages, and the second voltage may be high voltages. The first voltage and the third voltage may be equal to each other, for example both equal to 0.

The optical axis of the first liquid crystal quarter-wave plate 24 and the optical axis of the second liquid crystal quarter-wave plate 27 are orthogonal to each other. The optical axis of the first liquid crystal quarter-wave plate 24 and the second liquid crystal quarter-wave plate 27 are orthogonal to each other. One wave plate 27 The angle between the optical axis and the optical axis of the linear polarizer 23 is 45 degrees, and the optical axis of the reflective polarizer 28 and the optical axis of the linear polarizer 23 are orthogonal to each other. For example, taking the polarized linear polarizer 23 as the reference angle of 0°, the first liquid crystal quarter-wave plate 24 and the second liquid crystal quarter-wave plate 27 that cooperate with the linear polarizer 23 to generate circularly polarized light The optical axis of one of the wave plates is +45°, the optical axis of the other wave plate is -45°, the optical axis of the reflective polarizer 28 is 90°, and the half-reflective half-lens 26 is a beam splitter that can detect any polarization. Half of the light is transmitted and half reflected, and there is no optical axis, so that the amount of light transmission and reflection can be better weighed.

In some embodiments, the first liquid crystal quarter-wave plate 24 and the second liquid crystal quarter-wave plate 27 may include, for example, a planar first electrode, a planar second electrode, and a planar first electrode. and a liquid crystal layer between the planar second electrode. By applying voltages to the respective planar first electrodes and the planar second electrodes, the arrangement state of the liquid crystal molecules in the respective liquid crystal layers can be changed, so that the first liquid crystal quarter wave plate 24 and the third liquid crystal quarter wave plate 24 can be changed. The two liquid crystal quarter wave plates 27 respectively have different optical states.

Both the first liquid crystal quarter-wave plate 24 and the second liquid crystal quarter-wave plate 27 have a first optical state and a second optical state. The first optical state may include, for example, a quarter wave plate (QWP) state, and the second optical state may include, for example, an off state.

When no voltage is applied to the electrodes of the first liquid crystal quarter-wave plate 24 and/or the second liquid crystal quarter-wave plate 27, the first liquid crystal quarter-wave plate 24 and/or the second liquid crystal quarter-wave plate 27 The first wave plate 27 is in the 1/4 wave plate state. When a voltage is applied to the electrodes of the first liquid crystal quarter-wave plate 24 and/or the second liquid crystal quarter-wave plate 27, the first liquid crystal quarter-wave plate 24 and/or the second liquid crystal quarter-wave plate 27 One wave plate 27 is in a flat state.

In some embodiments, the display system 20 of the embodiment of the present application may further include a controller (not shown). The controller can respectively control the voltages applied to the electrodes of the first liquid crystal quarter-wave plate 24 and the electrodes of the second liquid crystal quarter-wave plate 27 to generate images with two depths of field. For example, the controller can control the first liquid crystal quarter-wave plate 24 to always be in the 1/4-wave plate state, and control the second liquid crystal quarter-wave plate 27 to be between the 1/4-wave plate state and the flat plate state. switch.

Table 1 below shows changes in the optical states of the first liquid crystal quarter-wave plate 24 and the second liquid crystal quarter-wave plate 27 when realizing images with two depths of field.

Table I

The two optical paths of the display system 20 in the embodiment of the present application will be described in detail below with reference to Figures 1 and 2 and Table 1.

As shown in FIG. 1 , when the first liquid crystal quarter-wave plate 24 is in the 1/4-wave plate state and the second liquid crystal quarter-wave plate 27 is in the flat state, the light emitted by the display module 21 is linearly polarized. The plate 23 generates linearly polarized light. For example, taking the light output of the linearly polarized plate 23 as 0° and the light efficiency as 1, the 0° linearly polarized light passes through, for example, a first liquid crystal quarter-wave plate placed with an optical axis of 45°. 24. At this time, since the first liquid crystal quarter-wave plate 24 is in the 1/4-wave plate state, it then becomes right-handed circularly polarized light. Then, the right-handed circularly polarized light passes through the first lens 25 and the semi-reflector in sequence. The polarization state of the half-mirror 26 remains unchanged, but since the half-reflective half-lens 26 transmits half of any polarized light and reflects half, the light effect becomes 1/2 at this time, and then passes through the second liquid crystal quarter in the flat state. A wave plate 27 does not change the polarization state, and finally reaches the reflective polarizer 28 as right-handed circularly polarized light. The transmission axis of the reflective polarizer 28 is 90°. At this time, it is directly emitted as 90° linearly polarized light. At this time, The overall light emission effect is 1/4, and the display system 20 has a straight first optical path. At this time, the display system 20 has a first focal length f1 and generates an image with a first depth of field D1.

As shown in FIG. 2 , when the first liquid crystal quarter-wave plate 24 and the second liquid crystal quarter-wave plate 27 are both in the 1/4-wave plate state, the light emitted by the display module 21 passes through the linear polarizer 23 , to generate linearly polarized light. For example, assuming that the light output of the linear polarizer 23 is 0° and the light efficiency is 1, the 0° linearly polarized light passes through the first liquid crystal quarter-wave plate 24 placed with an optical axis of 45°, for example. At this time, since the first liquid crystal quarter-wave plate 24 is in the 1/4-wave plate state, it then becomes right-hand circularly polarized light. Then, the right-hand circularly polarized light passes through the first lens 25 and the half-reflective half-lens in sequence. 26, the polarization state remains unchanged, but due to the half-reflective half-mirror 26 means that half of the light is transmitted and half is reflected for any polarized light. Therefore, the light efficiency becomes 1/2 at this time, and the right-handed circularly polarized light reaches the second liquid crystal quarter-wave plate 27 in the 1/4-wave plate state. Since the first The optical axis of the second liquid crystal quarter-wave plate 27 is orthogonal to the optical axis of the first liquid crystal quarter-wave plate 24, and the optical axis of the second liquid crystal quarter-wave plate 27 is -45°. At this time, The right-handed circularly polarized light returns to 0° linearly polarized light after passing through the second liquid crystal quarter-wave plate 27. The 0° linearly polarized light reaches the reflective polarizer 28 and is reflected because the reflective polarizer 28 transmits 90° linearly polarized light. 0° linearly polarized light. Therefore, the 0° linearly polarized light is reflected back after being incident on the reflective polarizer 28; when it passes through the second liquid crystal quarter-wave plate 27 in the 1/4-wave plate state for the second time, it becomes right again. Circularly polarized light, this right-handed circularly polarized light passes through the half-reflective semi-lens again and the polarization changes to left-handed circularly polarized light. At this time, the light effect becomes 1/4; the left-handed circularly polarized light passes through the 1/4 wave plate for the third time The second liquid crystal quarter-wave plate 27 in the state then becomes 90° linearly polarized light. Since the reflective polarizer 28 transmits 90° linearly polarized light and reflects 0° linearly polarized light, the 90° linearly polarized light can then be Light is emitted from the reflective polarizer 28. At this time, the overall light emission effect is 1/4. The polarized light is reflected once between the semi-reflective mirror 26 and the reflective polarizer 28 and then emerges from the reflective polarizer 28. The display system 20 has a second optical path that is folded (pancake). At this time, the display system 20 has a second focal length f2 and An image with a second depth of field D2 is produced.

As shown in FIGS. 1 and 2 , the second focal length f2 of the display system 20 is smaller than the first focal length f1 , and the second depth of field D2 is larger than the first depth of field D1 .

When the refresh frequency displayed by the display system 20 is N Hz (N=45, 60, 72, 90 or higher), the display module 21 needs to transmit the film sources required for the close-up and distant views respectively at 2N, and At the same time, the second liquid crystal quarter-wave plate 27 switches between the flat state and the 1/4-wave plate state at 2N. That is to say, within 1/2N s (second), the close-up view given by the display module 21, the first The second liquid crystal quarter-wave plate 27 is powered on to obtain the flat state; after 1/2N s, the display module 21 switches to the distant view, and at the same time the second liquid crystal quarter-wave plate 27 switches to the 1/4-wave plate state. , and continuously alternate with this sequence to achieve VR display with multiple depths of field per eye.

The display system 20 of the embodiment of the present application uses a switchable liquid crystal wave plate, and the voltage applied to the liquid crystal wave plate can cause the liquid crystal wave plate to switch between two optical states at a higher frequency. By changing and matching with other optical devices, two different focal lengths and virtual image distances can be generated, and the 2D film source of the display module 21 can be used to display different information at two times. Through time division multiplexing, people can see to two images with different virtual image distances to achieve single-eye multi-depth VR display.

In some embodiments, the reflective polarizer 28 is a wire grid polarizer (WGP, Wire Grid Polarizer), and the wire grid polarizer can be integrated on the second liquid crystal quarter-wave plate 27 . Wire grid polarizer is a wire grid metal design that transmits light of one polarization state while reflecting light of another polarization state.

The reflective polarizer 28 in the display system 20 of the embodiment of the present application is integrated on the second liquid crystal quarter-wave plate 27 using WGP, thereby further improving the resource utilization of the overall system, and there is no attachment problem.

In some embodiments, the semi-reflective mirror 26 is a semi-reflective film coated on the second liquid crystal quarter-wave plate 27 .

In some embodiments, the display system 20 may also include a second lens 29. The second lens 29 is located in the light path from the reflective polarizer 28 to the eye side, so that it can be used to change the focal length of the display system 20 and send the generated image to Specify the depth of field position, and the imaging quality can be changed. In FIGS. 1 and 2 it is shown that the display system 20 includes a second lens 29 . However, the display system 20 of the embodiment of the present application is not limited to including only one second lens 29 . In other embodiments, the display system 20 of the embodiment of the present application may not include a second lens, or may include more second lenses.

In the first embodiment described above, the display system 20 realizes images with two depths of field by switching between two optical states of the second liquid crystal quarter-wave plate 27 . In order to make the effect of three-dimensional image fusion more delicate, the display system of the second embodiment is also provided below.

Second embodiment

Figure 3 reveals a schematic diagram of the light path of the display system 30 according to the second embodiment of the present application when it has a first light path. Figure 4 reveals a schematic diagram of the light path of the display system 30 of the second embodiment of the present application when it has a second light path; Figure 5 A schematic diagram of the optical path of the display system 30 according to the second embodiment of the present application when it has a third optical path is disclosed; Figure 6 discloses a schematic diagram of the display system 30 when it has a fourth optical path according to the second embodiment of the present application. Schematic diagram of the optical path. Referring to FIGS. 3 to 6 , what is different from the display system 20 of the first embodiment is that the display system 30 of the second embodiment further includes a switchable half-wave plate. In some embodiments, the switchable half-wave plate includes a liquid crystal half-wave plate 31 . Of course, the switchable half-wave plate in the embodiment of the present application is not limited to the form of a liquid crystal wave plate. In other embodiments, the switchable half-wave plate in the embodiment of the present application can also be in the form of other wave plates that can change the wave plate. achieved in the form of optical states. The following is a schematic explanation taking the switchable half-wave plate as the liquid crystal half-wave plate 31 as an example.

The liquid crystal half-wave plate 31 is located in the optical path between the display module 21 and the first liquid crystal quarter-wave plate 24 . The angle between the optical axis of the liquid crystal half-wave plate 31 and the optical axis of the linear polarizer 23 is 22.5 degrees.

Similarly, the liquid crystal half-wave plate 31 has electrodes and a liquid crystal layer 313 between the electrodes. The liquid crystal half-wave plate 31 can have different optical states when driven by different voltages.

FIG. 7 reveals a schematic diagram of the optical path of the liquid crystal half-wave plate 31 before and after power-on according to an embodiment of the present application. As shown in FIG. 7 , in some embodiments, the liquid crystal half-wave plate 31 (HWP, Half Wave Plate) may include, for example, a planar first electrode 311 , a planar second electrode 312 , and a planar first electrode 312 . 311 and the planar second electrode 312. By applying a voltage to the planar first electrode 311 and the planar second electrode 312, the arrangement state of the liquid crystal in the liquid crystal layer 313 can be changed, so that the liquid crystal half-wave plate 31 can have different optical states.

The liquid crystal half-wave plate 31 may have a second optical state and a fifth optical state. The second optical state includes a plate state, and the fifth optical state may include, for example, a 1/2 wave plate state.

Referring to FIG. 7 , when no voltage is applied to the electrodes of the liquid crystal half-wave plate 31 , the liquid crystal molecules in the liquid crystal layer 313 of the liquid crystal half-wave plate 31 maintain the initial horizontal arrangement, and the liquid crystal half-wave plate 31 is in the initial 1/2 wave. At this time, the refractive index of the liquid crystal half-wave plate 31 is relatively large. When a voltage is applied to the electrodes of the liquid crystal half-wave plate 31, the liquid crystal molecules in the liquid crystal layer 313 of the liquid crystal half-wave plate 31 are arranged vertically, and the liquid crystal half-wave plate 31 is in a flat state. At this time, the liquid crystal half-wave plate 31 The refractive index is smaller.

What is also different from the display system 20 of the first embodiment is that, as shown in FIG. 8 , in the display system 30 of the second embodiment, the electrodes of the second liquid crystal quarter-wave plate 37 include a plurality of staggered arrangements. ring The liquid crystal layer 373 is located between the plurality of annular electrodes 371 . By applying different voltages to the ring electrode 371, the arrangement state of the liquid crystal molecules in the liquid crystal layer 373 can be changed, so that the second liquid crystal quarter-wave plate 37 can have multiple different optical states.

In one embodiment, the second liquid crystal quarter-wave plate 37 may further have a third optical state and a fourth optical state in addition to the first optical state and the second optical state mentioned in the first embodiment. state. The third optical state may include, for example, a Fresnel convex lens state, and the fourth optical state may include, for example, a Fresnel concave lens state.

FIG. 9 reveals a schematic diagram of the optical path of the second liquid crystal quarter-wave plate 37 under application of different voltages according to an embodiment of the present application. As shown in FIG. 9 , when the second voltage Vop2 is applied to the entire surface of the annular electrode 371 of the second liquid crystal quarter-wave plate 37 , the second liquid crystal quarter-wave plate 37 is in the 1/4-wave plate state. , the second liquid crystal quarter-wave plate 37 has a large refractive index; when the third voltage Vop3 is applied to the entire surface of the annular electrode 371 of the second liquid crystal quarter-wave plate 37, the second liquid crystal quarter-wave plate 37 has a large refractive index. 37 is in a flat state. At this time, the second liquid crystal quarter-wave plate 37 has a very small refractive index; when the fourth voltage Vop4 is applied to the ring electrode 371 of the second liquid crystal quarter-wave plate 37, the second liquid crystal quarter-wave plate 37 The quarter-wave plate 37 is in the Fresnel convex lens state; when the fifth voltage Vop5 is applied to the annular electrode 371 of the second liquid crystal quarter-wave plate 37, the second liquid crystal quarter-wave plate 37 is in the Fresnel state. concave lens state.

In one embodiment, the applied second voltage Vop2 is greater than the third voltage Vop3, the applied fourth voltage Vop4 and the fifth voltage Vop5 are respectively between the second voltage Vop2 and the third voltage Vop3, and the fourth voltage Vop4 and the fifth voltage Vop5 is the gradient voltage. For example, when the second liquid crystal quarter-wave plate 37 is in the Fresnel convex lens state, the voltage applied to the ring electrode 371 of the outermost ring is the highest and the refractive index is the lowest, which is equivalent to the edge area of the convex lens; and the middle one has the highest voltage and the lowest refractive index. The voltage applied to the annular electrode 371 of that ring is the lowest and has the highest refractive index, which is equivalent to the bulging part in the middle of the convex lens. When the second liquid crystal quarter-wave plate 37 is in the concave Fresnel lens state, the applied voltage is opposite.

In the second embodiment, the controller (not shown) in the display system 30 can respectively apply The voltages on the first liquid crystal quarter-wave plate 24, the second liquid crystal quarter-wave plate 37 and the liquid crystal half-wave plate 31 are controlled to generate images with four depths of field. For example, the controller can control the first liquid crystal quarter-wave plate 24 to switch between the 1/4-wave plate state and the flat plate state, and control the second liquid crystal quarter-wave plate 37 to switch between the 1/4-wave plate state, Switch between the flat plate state, the Fresnel convex lens state and the Fresnel concave lens state, and control the liquid crystal half-wave plate 31 to switch between the 1/2 wave plate state and the flat plate state.

Table 2 below shows changes in the optical states of the liquid crystal half-wave plate 31, the first liquid crystal quarter-wave plate 24, and the second liquid crystal quarter-wave plate 37 when realizing images with four depths of field.

Table II

The four optical paths of the display system 30 in the embodiment of the present application will be described in detail below with reference to FIGS. 3 to 6 and Table 2.

As shown in Figure 3, when the liquid crystal half-wave plate 31 is in the flat state, the first liquid crystal quarter-wave plate 24 is in the 1/4-wave plate state, and the second liquid crystal quarter-wave plate 37 is in the flat state, the display The light emitted by the module 21 passes through the linear polarizer 23 to generate linearly polarized light. For example, assuming that the light output of the linear polarizer 23 is 0° and the light efficiency is 1, the 0° linearly polarized light passes through the half-wave of the liquid crystal in the flat state. plate 31, without changing the polarization state, the 0° linearly polarized light directly enters the first liquid crystal quarter wave plate 24, and passes through the 1/4 The first liquid crystal quarter-wave plate 24 in the wave plate state then becomes right-handed circularly polarized light. Then, the right-handed circularly polarized light passes through the first lens 25 and the half-reflective half-lens 26 in sequence, and the polarization state remains unchanged. However, since the half-reflective mirror 26 transmits half of any polarized light and reflects half, the light efficiency becomes 1/2 at this time, and then passes through the second liquid crystal quarter-wave plate 37 in the flat state without changing the polarization state. Finally, the right-hand circularly polarized light reaches the reflective polarizer 28. The transmission axis of the reflective polarizer 28 is 90°. At this time, the 90° linearly polarized light is directly emitted. At this time, the overall light emission effect is 1/4, and the display system 30 has a straight first optical path. At this time, the display system 30 has a first focal length f1 and generates an image with a first depth of field D1.

As shown in Figure 4, when the liquid crystal half-wave plate 31 is in the flat state, and the first liquid crystal quarter-wave plate 24 and the second liquid crystal quarter-wave plate 37 are both in the 1/4-wave plate state, the display module The light emitted by 21 passes through the linear polarizer 23 to produce linearly polarized light. For example, taking the light output of the linear polarizer 23 as 0° and the light efficiency as 1, the 0° linearly polarized light passes through the liquid crystal half-wave plate 31 in a flat state. , without changing the polarization state, the 0° linearly polarized light directly enters the first liquid crystal quarter-wave plate 24. At this time, since the first liquid crystal quarter-wave plate 24 is in the 1/4-wave plate state, it then becomes Right-hand circularly polarized light, then, this right-hand circularly polarized light passes through the first lens 25 and the half-reflective half-lens 26 in sequence, and the polarization state remains unchanged. However, since the half-reflective half-lens 26 transmits half and reflects half of any polarized light, Therefore, the light efficiency becomes 1/2 at this time, and the right-hand circularly polarized light reaches the second liquid crystal quarter-wave plate 37 in the 1/4-wave plate state. At this time, the right-hand circularly polarized light passes through the second liquid crystal quarter-wave plate 37. After the half-wave plate 37 returns to 0° linearly polarized light, the 0° linearly polarized light reaches the reflective polarizer 28. Since the reflective polarizer 28 transmits 90° linearly polarized light and reflects 0° linearly polarized light, therefore, 0° The linearly polarized light is reflected back after entering the reflective polarizer 28; when it passes through the second liquid crystal quarter-wave plate 37 in the 1/4-wave plate state for a second time, it becomes right-handed circularly polarized light again. The right-handed circularly polarized light After the light passes through the half-reflective half-lens again, the polarization changes to left-handed circularly polarized light. At this time, the light efficiency becomes 1/4; the left-handed circularly polarized light passes through the second liquid crystal quarter wave in the 1/4 wave plate state for the third time. After the film 37, it becomes 90° linearly polarized light. Since the reflective polarizer 28 transmits the 90° linearly polarized light and reflects the 0° linearly polarized light, the 90° linearly polarized light can then emerge from the reflective polarizer 28. At this time, The overall light emission effect is 1/4. The polarized light is reflected once between the semi-reflective mirror 26 and the reflective polarizer 28 and then emerges from the reflective polarizer 28. The display system 30 has a second optical path that is folded (pancake). At this time, The display system 30 has a second focal length f2 and generates an image with a second depth of field D2. The second focal length f2 is smaller than the first focal length f1, and the second depth of field D2 is larger than the first depth of field D1.

As shown in Figure 5, the liquid crystal half-wave plate 31 is in the 1/2-wave plate state, the first liquid crystal quarter-wave plate 24 is in the flat plate state, and the second liquid crystal quarter-wave plate 37 is in the Fresnel convex lens state. When , since the liquid crystal half-wave plate 31 is in the 1/2-wave plate state, for example, the 0° linearly polarized light passing through the linear polarizer 23 is modulated to 90° linearly polarized light (and the first liquid crystal quarter-wave plate 24 (the optical axis is consistent), and then passes through the first liquid crystal quarter wave plate 24, the first lens 25 and the half mirror 26 in the flat state in sequence, the polarization state remains unchanged, and the 90° linearly polarized light reaches the second Liquid crystal quarter-wave plate 37. At this time, since the second liquid crystal quarter-wave plate 37 is in the Fresnel convex lens state, the 90° linearly polarized light does not change after passing through the second liquid crystal quarter-wave plate 37. The polarization state is finally directly emitted from the reflective polarizer 28 (which transmits 90° linearly polarized light and reflects 0° linearly polarized light). The display system 30 has another direct third optical path. At this time, the display system 30 has a third focal length. f3 and produces an image of the third depth of field D3, and the third focal length f3 is smaller than the second focal length f2, and the third depth of field D3 is larger than the second depth of field D2.

As shown in FIG. 6 , the liquid crystal half-wave plate 31 is in the 1/2-wave plate state, the first liquid crystal quarter-wave plate 24 is in the flat plate state, and the second liquid crystal quarter-wave plate 37 is in the Fresnel concave lens state. When , since the liquid crystal half-wave plate 31 is in the 1/2-wave plate state, for example, the 0° linearly polarized light passing through the linear polarizer 23 is modulated to 90° linearly polarized light (and the first liquid crystal quarter-wave plate 24 (the optical axis is consistent), and then passes through the first liquid crystal quarter wave plate 24, the first lens 25 and the half mirror 26 in the flat state in sequence, the polarization state remains unchanged, and the 90° linearly polarized light reaches the second Liquid crystal quarter-wave plate 37. At this time, since the second liquid crystal quarter-wave plate 37 is in the Fresnel concave lens state, the 90° linearly polarized light does not change after passing through the second liquid crystal quarter-wave plate 37. The polarization state is finally directly emitted from the reflective polarizer 28, and the display system 30 has another direct fourth optical path. At this time, the display system 30 has a fourth focal length f4 and generates an image with a fourth depth of field D4, and the fourth The focal length f4 is greater than the first focal length f1, and the fourth depth of field D4 is less than the first depth of field D1.

The images of the above four depths of field can be switched at high frequency, so that the remaining images in human vision can be Finally, it is merged into a three-dimensional effect to achieve a single-eye multi-depth VR display with more detailed images.

An embodiment of the present application also provides a display device. The display device may include the display system described in each of the above embodiments.

In one embodiment, the display device may be a virtual reality display device. In another embodiment, the display device may be an augmented reality display device.

The display device according to the embodiment of the present application has substantially similar beneficial technical effects to the display system described above, and therefore will not be described again here.

The display system and display device provided by the embodiments of the present application have been introduced in detail above. This article uses specific examples to illustrate the display system and display device of the embodiments of the present application. The description of the above embodiments is only used to help understand the core idea of the present application and is not intended to limit the present application. It should be pointed out that for those of ordinary skill in the art, several improvements and modifications can be made to the present application without departing from the spirit and principles of the present application, and these improvements and modifications should also fall into the appendix of the present application. within the scope of protection of the claims.

Claims

A display system, characterized in that it includes a display module for emitting light. A linear polarizer is attached to the display module for generating linearly polarized light. The display system is connected from the display module to The light path on the eye side also includes a switchable first quarter-wave plate, a first lens, a half-reflective half-mirror, a switchable second quarter-wave plate, and a reflective polarizer. The first quarter-wave plate Both the first quarter-wave plate and the second quarter-wave plate have electrodes, the first quarter-wave plate is driven at a first voltage and the second quarter-wave plate is driven at a second voltage. Drive down to cause the display system to produce an image with a first depth of field, the first quarter-wave plate is driven at the first voltage and the second quarter-wave plate is driven at a third voltage So that the display system generates an image with a second depth of field, wherein the first depth of field is different from the second depth of field.
The display system of claim 1, wherein the reflective polarizer is a wire grid polarizer, and the wire grid polarizer is integrated on the second quarter wave plate.
The display system according to claim 1, further comprising one or more second lenses, the one or more second lenses are located in the optical path from the reflective polarizer to the eye side.
The display system of claim 1, wherein the optical axis of the first quarter-wave plate and the optical axis of the second quarter-wave plate are orthogonal to each other, and the reflective polarizer The optical axis of and the optical axis of the linear polarizer are orthogonal to each other.
The display system according to any one of claims 1 to 4, wherein the first quarter-wave plate has a first optical state, and the second quarter-wave plate has the third optical state. An optical state and a second optical state, wherein when the first quarter-wave plate is in the first optical state and the second quarter-wave plate is in the second optical state, the The display system has a first optical path and a first focal length and produces an image of the first depth of field; when both the first quarter-wave plate and the second quarter-wave plate are in the first optical state, the display system has a second optical path and a second focal length and produces an image with the second depth of field, and the second focal length is smaller than the first focal length, and the second depth of field is greater than the first depth of field. .
The display system of claim 5, wherein the first optical state includes 1/4 wave plate state, the second optical state includes a flat plate state.
The display system of claim 5, further comprising a controller configured to control an electrode applied to the first quarter-wave plate and the second quarter-wave plate. The voltages on the electrodes are controlled to produce images with two depths of field.
The display system of claim 5, further comprising a switchable half-wave plate located in the optical path between the display module and the first quarter-wave plate. , the half-wave plate has electrodes, and the half-wave plate has different optical states when driven by different voltages.
The display system of claim 8, wherein the half-wave plate has the second optical state, and when the display system has the first optical path or the second optical path, the half-wave plate The pieces are all in the second optical state.
The display system of claim 9, wherein the first quarter-wave plate also has the second optical state, and the second quarter-wave plate also has a third optical state, The half-wave plate also has a fifth optical state, wherein the half-wave plate is in the fifth optical state, the first quarter-wave plate is in the second optical state, and the second When the quarter-wave plate is in the third optical state, the display system has a third optical path and a third focal length and produces an image with a third depth of field, and the third focal length is smaller than the second focal length, so The third depth of field is greater than the second depth of field.
The display system of claim 10, wherein the second quarter-wave plate further has a fourth optical state, and when the half-wave plate is in the fifth optical state, the first four-wave plate When the quarter-wave plate is in the second optical state and the second quarter-wave plate is in the fourth optical state, the display system has a fourth optical path and a fourth focal length and generates a fourth depth of field. image, and the fourth focal length is greater than the first focal length, and the fourth depth of field is less than the first depth of field.
The display system of claim 11, wherein the electrodes of the second quarter-wave plate include a plurality of annular electrodes arranged in a staggered manner.
The display system of claim 12, wherein when the second voltage is applied to the entire surface of the annular electrode of the second quarter-wave plate, the second quarter-wave plate is in the the first optical state; applying the third electric current to the entire surface of the annular electrode of the second quarter-wave plate When voltage is applied, the second quarter-wave plate is in the second optical state; when the ring electrode of the second quarter-wave plate applies a fourth voltage or a fifth voltage respectively, the second quarter-wave plate The quarter wave plate is in the third optical state or the fourth optical state respectively.
The display system of claim 13, wherein the fourth voltage and the fifth voltage are respectively between the second voltage and the third voltage, and the fourth voltage and The fifth voltage is a gradient voltage.
The display system of claim 11, wherein the first optical state includes a quarter-wave plate state, the second optical state includes a flat plate state, and the third optical state includes a Fresnel convex lens state. , the fourth optical state includes a Fresnel concave lens state, and the fifth optical state includes a 1/2 wave plate state.
The display system of claim 11, further comprising a controller configured to control electrodes applied to the first quarter-wave plate, the second quarter-wave plate The voltages on the electrodes and the half-wave plate electrodes are controlled to produce images with four depths of field.
The display system of claim 8, wherein the first quarter-wave plate includes a first liquid crystal quarter-wave plate; and/or the second quarter-wave plate includes a second liquid crystal quarter-wave plate; and/or the half-wave plate includes a liquid crystal half-wave plate.
A display device, characterized by comprising the display system according to any one of claims 1 to 17.